之前执行了pip3 install -U leancloud以及在新的虚拟机中用pip3安装leancloud后执行脚本报以下错误：
Traceback (most recent call last):
File "notifier.py", line 9, in <module>
import leancloud
File "/usr/local/lib/python3.6/dist-packages/leancloud/__init__.py", line 19, in <module>
from . import client
File "/usr/local/lib/python3.6/dist-packages/leancloud/client.py", line 18, in <module>
from leancloud import utils
File "/usr/local/lib/python3.6/dist-packages/leancloud/utils.py", line 16, in <module>
from werkzeug import LocalProxy
ImportError: cannot import name 'LocalProxy'
